With advances in technology, the size of various compact electronic devices, such as mobile phones, has become smaller. A common way to implement a phone which is small and thereby convenient to carry along but still easy to use, is to make the phone of two parts which are folded when the phone is not used. These so-called fold devices have quickly become common and gained popularity among users particularly because a small portable size and a sufficient usage size are combined in the flip-up structure.
An essential part in the foldable device is its hinge structure. The hinge structure must allow opening and closing of the device in an easy and reliable way. Furthermore, it must be durable in the intended use and generally also make data transmission possible between different parts of the device.
One hinge structure is disclosed in U.S. Pat. No. 6,079,993 presenting a hinge system with two hinge means and the coupling of the body parts with a cable. In particular, this publication presents such a solution for placing the cable that is applicable in portable devices, for example personal digital assistants, which are opened and closed relatively frequently. Such devices are normally used in a less frequent and more device friendly way than mobile phones. For this reason, hinge structures for mobile phones have been developed to be resistant to heavier and more frequent use.
U.S. Pat. No. 6,692,275 B2 presents a hinge structure for a mobile phone, and particularly a solution for placing the wiring through the hinge structure (a flexible printed circuit board). This solution is intended particularly for mobile phones which are opened and closed very often, wherein the hinge structure and the wiring are subjected to frequently repeated loads. The presented hinge structure extends to the whole length of the back, as does the majority of hinge structures in mobile phones. The hinge structure comprises edge parts and a middle part arranged to be pivoted therebetween. The edge parts are connected to the first body part, and the middle part is connected to the second body part. The wiring is arranged to extend from the first body part through the edge part and the middle part of the hinge structure to the second body part. Said publication presents a particular hinge pin structure by which loads on the wiring can be reduced when compared with corresponding hinge arrangements equipped with different hinge pins.
The conventional hinge structures for mobile phones are relatively complex, wherein the assembly of the device requires work stages which increase the costs. Furthermore, the hinge structures extending over the whole back of the device require a lot of space compared to the other structures, wherein the size of the whole device becomes larger due to the hinge structure.